It wasn’t too long ago that the average tween boy didn’t see any reason to bathe, groom, and for sure, to use cologne or deodorant. Certainly, countless fifth grade teachers have been forced into interventions in the post-gym class hours. But these days, thanks to Unilever and Procter & Gamble (P&G), tween boys are not only complying with, but requesting personal care products that are marketed with them in mind.

When Axe’s (Unilever) breakthrough advertising hit the scene a few years ago, they hit the mark with tween boys. The original U.S. TV spots (Axe has been around since the 80s in France and other markets), which showed more than telling young men, “wear this deodorant and girls won’t be able to resist you,” adopt a strategy characterized by both hyperbole and satire. These brands poke fun at a category in which ads have traditionally taken themselves very seriously, implying that choosing the right anti-perspirant can make them as aspirational as a star athlete or prevent them from a blunder at a big meeting. And silly seems to have led to sales among tween boys who want nothing more to avoid serious conversations about personal hygiene and body odor.

Old Spice (P&G) has attempted to reinvent itself in the same vane. From our outsider perspective, it seems the insight is similar to the one Axe employs…Boys are a bit uncomfortable with traditional expectations of masculinity and relish seeing someone find the chink in the armor. And in Old Spice’s latest campaign, we see the very manly main character, Old Spice Man ride a white stallion, dive from the top of a waterfall, and straddle a very large motorcycle – and for good measure, he cooks a gourmet meal along the way. This exaggerated image of the ideal man is not lost on tweens – the campaign has been one of the most viral ones on YouTube (where tween boys are practically the ruling class).

Interestingly, Old Spice’s first go, “Red Zone,” felt a bit safe and couldn’t find a way to stand out among boys. Their packaging relaunch includes a new name: “Swagger.” Clearly, the lesson learned by P&G is that this is not your dad’s Old Spice – and you’ve got to take a few risks to prove it. (Because we know that no actual tween boys read this blog, we’ll let you in on a secret…This strategy is similar to Kotex’s approach to reinventing the feminine hygiene category, which we discussed in a previous blog entry. But please don’t tell the tween boys you know!)

But what else does this tell us about the challenge of disrupting staid and mature categories for the younger set?

First, both brands dared to go younger – despite what we imagine market research told them…This is where the art needs to inform the science. We imagine that the numbers might have told them that moms are buying deodorant for their tween boys – and that there is a much larger men’s market than boy’s. But we know from our own data that deodorant is the item that tweens in general report influencing the most – next to clothes and shoes. In 2009, 51% of tween boys said that they have “a lot” of influence over this purchase, and we know that, in the youth market, influence matters as much as money from your own pocket. And they probably noticed that most men were buying (or asking someone else to buy) the same brand of deodorant that they’ve been using since their teen years. So going younger seemed almost an inevitable market strategy – that no one else was really embracing.

Second, they learned that going after this market requires commitment. And it might require, on the surface, alienating your more serious customers. But mom doesn’t seem to be turned off by the edgy campaigns from either brand. In fact, she’s likely to be smiling all the way to the drugstore…Most moms are willing to indulge their tweens if it means making a tricky conversation about taking care of one’s self avoidable. Launching ads that encourage boys to “get some action” might invite a few letters from those people who write letters about ads that they deem offensive, but for tween boys, “going there” is part of the fun.

Finally, they took a category that felt formulaic and changed the rules. Each year, Axe launches a new line of fragrances – and ones that signal that they’re talking to a younger, more daring demo. Axe’s “Twisted Humor Tour,” in partnership with Funny or Die and its “Undie Runs” for charity (which challenges college kids to participate and tweens to snort with laughter) are probably difficult to measure with traditional metrics. And the old-fashioned look that characterized the first round of Old Spice Red Zone (sorry, P&G!) has given way to an aesthetic that shows that the brand is willing to leave a few good men behind.

So what’s the bottom line? Taking a chance on tweens means taking a few risks…But with tweens, a little risk-taking can yield unexpected returns.